The present invention relates to an apparatus for levitating an object by radiation pressure such as sound waves and transporting the levitated object.
Japanese Unexamined Patent Publications No. 7-137824 and No. 9-202425 disclose apparatuses for levitating an object. These apparatuses include elongated plate-like vibrators, which are excited, or vibrated, by transducers. The surface of the levitated object that faces the vibrators is formed flat. The object is levitated by radiation pressure of sound waves, which are generated by vibration of the vibrators. A transporting apparatus that moves a levitated object by blasting air or by producing traveling waves with vibrators has also been proposed.
If vibrators are relatively long, the vibrators are bent by the own weight and the weight of a transported object. Thus, the vertical position of each vibrator varies at the longitudinal center and the ends. This hinders stable transportation of levitated objects. If the interval between each pair of adjacent transducers, which excite the vibrators, is short, the vibrators are not bent. However, this increases the number of the transducers and thus increases the cost. Also, if a transporting apparatus has two or more parallel vibrators, the levitation state of a transported object is unstable since the vibrators are bent at different degrees.
Accordingly, it is an objective of the present invention to provide a transporting apparatus that uses elongated plate-like vibrators and prevents the vibrators from being bent by the own weight and the weight of the transported object thereby transporting objects in a stable manner.
To achieve the purpose of the present invention, an apparatus for levitating and transporting an object is provided. The apparatus includes an elongated vibrator, an oscillator, and a flection limiting member. The oscillator vibrates the vibrator to generate sound waves from the vibrator. The object is levitated by radiation pressure of the sound waves. The flection limiting member contacts the lower surface of the vibrator for reducing the flection of the vibrator due to the weight of the vibrator and the weight of the transported object.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.